From global to regional scale:Impact of road traffic emissions on tropospheric ozone

Mariano Mertens1*, Eleni Tsati1, Astrid Kerkweg2, Volker Grewe1 and Patrick Jöckel1 1 Institute for Atmospheric Physics, DLR, Oberpfaffenhofen, Germany2 Institute for Atmospheric Physics, University of Mainz, Germany

CLM Community Assembly 2014

* Mariano.Mertens@dlr.de

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a long title

from global to regional scale

impact

road traffic

tropospheric ozone

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from global to regional scale

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road traffic emissions

- anthropogenic source for CO, NMHCs and NOx

- precursors for the formation of tropospheric ozone- impact on climate, health and vegetation

CO

NOx

NMHC

0 5 10 15 20 25 30 35 40 45 50

18.6

6.7

3.37

45.81

15.74

11.97

antropoghenic emissions 2008 (European domain)

road traffictotal

Tg specie

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simplified ozone chemistry

sources: combustion (industry, road traffic),lightning

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simplified ozone chemistry

sources: combustion (industry, road traffic),lightning

sources:biogenic,road traffic,industry

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ozone chemistry is strongly non linear

adapted from:The Royal Society,Ground-level ozone in the 21st century

NOx limited NMHC limited

prod

uctio

nlo

ss

NMHC

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global models

- typical resolution of global CCMs > 200 km- cities are not resolved explicitly

ground-level ozone in Europe (June 08)(T42 resolution)

What happens if the horizontal resolution is increased?

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quantifying the impact of different sources

- perturbation approach:- comparison of reference and perturbed simulation- liniarization assuming same background chemistry

- TAGGING approach: - accounting system following the relevant reaction

pathways

Grewe at al. 2012

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simple example of the TAGGING method

- the basic idea (more details see Grewe, 2013):- track the reaction path of the species from different sources

OHNO2HNO3∂HNO3

∂ t=OH⋅NO2=PHNO3

∂HNO3j

∂ t=12PHNO3

OH j

OHNO2

j

NO2

write as

ODE

tag it!

HNO3 formed by sector j

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MECO(n) model system

Kerkweg & Jöckel, 2012

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setup

- MECO(1)- based on the REF-C1SD setup for ESCiMo consortia simulations1

- T42L31ECMWF for EMAC- Nudged with ECMWF operational analysis data

- 0.44° x 0.44° COSMO/MESSy nest over Europe- MECCA and TAGGING running regional and global- LNOX and biogenic emissions calculated globally, transformed to region- anthropogenic emissions based on MACCity2 database (0.5° resolution)

1 http://www.pa.op.dlr.de/~PatrickJoeckel/ESCiMo/2 eccad.sedoo.fr

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first steps of the chemical evaluation

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ground-level ozone concentration (January 2008)

station data from ebas.nilu.no

general positive ozone biasCOSMO/MESSy with better results especially over the south of France

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ground-level ozone concentration (May 2008)

station data from ebas.nilu.no

COSMO/MESSy with better results over England, France and Germanytoo much ozone over Northern and Eastern Europe in COSMO/MESSy

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ozone zonal-mean (May 08)

zonal means look similar; difference only present in pbl reason: chemistry? dynamics (e.g. too stable boundary layer)?

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first results

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ozone production efficiency (avg. up to 850hPa)

=1HO2⋅NO

2OH⋅NO2=PO3LNOX

ratio of O3 molecules produced/ NOx molecules consumed,

assuming reaction with OH is only sink of NO2 and NOx

steady state

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ozone production efficiency (avg. up to 850hPa)

pattern looks very similar; slightly higher values over North-/East Europe in COSMO/MESSy

May 2008

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contribution of different sources (COSMO/MESSy)

- contribution of road traffic doubles (Jan - Jun) from ~ 2.5 – 5 DU- contribution of industry almost doubles (Jan - Jun) from ~6 – 11 DU- stratospheric contribution peaks in March (~20 DU)- results for EMAC are comparable, but less ozone from stratosphere

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conclusion & outlook

- model chain with MECO(n), MECCA and TAGGING is technically working- allowing direct comparison of global and regional effects

- comparison with observations benefits from increased resolution- contribution of sectors to ozone in the European area doesn't change

significantly going from 2.8° - 0.44° resolution (in the simulated period).

- further evaluation, detailed analysis of TAGGING results- reason for too high ozone concentrations in the pbl will be analyzed- regional emissions database will be tested (ozone bias)

- calculation of lightning and biogenic emissions in COSMO/MESSy- further increase of resolution